content: /*
   * Copyright 2016-present David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.rxjava3.basetypes;
  
  import java.util.*;
  import java.util.concurrent.Callable;
  
  import org.reactivestreams.Subscriber;
  
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.internal.subscriptions.DeferredScalarSubscription;
  
  /**
   * Executes a callable and signals its resulting value.
   *
   * @param <T> the value type
   */
  final class SoloFromCallable<T> extends Solo<T> implements Callable<T> {
  
      final Callable<T> callable;
  
      SoloFromCallable(Callable<T> callable) {
          this.callable = callable;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super T> s) {
          DeferredScalarSubscription<T> dss = new DeferredScalarSubscription<>(s);
          s.onSubscribe(dss);
  
          T v;
  
          try {
              v = call();
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              s.onError(ex);
              return;
          }
  
          if (v != null) {
              dss.complete(v);
          } else {
              s.onError(new NoSuchElementException());
          }
      }
  
      @Override
      public T call() throws Exception {
          return Objects.requireNonNull(callable.call(), "The callable returned a null value");
      }
  }
  